US2387963A - Fire extinguishing method and apparatus - Google Patents

Description

Oct. 30, 1945. H. v. WILLIAMSON 2,337,963

4 FIRE EXTINGUISHING METHOD AND APPARATUS Filed Dec. 15, 1943 3 Sheets-Sheet l FIRE EXTINGUISHING METHOD AND APPARATUS g xy;

Patented Oct. 30, 1945 FIRE EXTINGUISHING METHOD AND APPARATUS Hilding V. Williamson, Chicago, IlL, assignor, by mesne assignments, to Reconstruction Finance Corporation, Chicago, 111., a corporation of the United States.

Application December 15, 1943, Serial No. 514,417

21 Claims.

This invention relates to new and useful improvements in methods and apparatus for extinguishing fires by means of a fire extinguishing medium formed of carbon dioxide and water 08. and constitutes improvements over the method and apparatus disclosed and claimed in the application to'Leonard D. Myers, Serial No. 492,458, filed June 26, 1943.

Water fog that is now commercially used by itself as a fire extinguishing medium and that is used in combination with carbon dioxide in accordance with the teachings of the aforesaid application is generated in an atomosphere of air. That is to say, the atomization or breaking up or the solid streams of water into fine, individual water droplets or particles to form the fog takes place in a zone that is surrounded by 'air. Consequently, the generated water fog is discharged from this zone with air filling the voids or spaces between the individual droplets or particles throughout the angle or projection of the fog discharge. This void or space filling air is carried to the zon of application of the water fog on the fire and provides the fire with combustion supporting oxygen.

It is one of the primary objects of this invention to generate in a carbon dioxide atmosphere water fog that is to beused in the extinguishment of fires.

A still further important object of the invention is the provision of a method of and apparatus for producing an improved fire extinguishing medium composed of pre-formed water g combined with carbon dioxide snow and vapor and in which the water fog is generated in an atmosphere of carbon dioxide so as to exclude air from the voids or spaces between the fine water droplets of the fog that is delivered to the carbon dioxide.

In my application Serial No. 425,568, filed January 3, 1942, I have disclosed and broadly claimed carbon dioxide discharge apparatus for use in extinguishing fires. By means of this apparatus liquid carbon dioxide is suddenly reduced in pressure to effect its conversion to a mixture of snow and vapor. Between the zone of pressure reduction and the zone of discharge to the atmosphere the snow or vapor mixture is manipulated so as to effect separation of the snow and vapor components. The final discharge stream is produced with the carbon dioxide snow forming its core and the carbon dioxid vapor forming a protective envelope around the snow. This discharge apparatus is of such construction that the carbon dioxide vapor is released to the atmosphere at a plurality of points or zones that are spaced circumferentially around the periphery of the dense snow core. Although these separate discharges of vapor flow or blend together by the time they have traveled a very short distance from the face of the discharge apparatus, and beyond their points of blending a solid or continuous envelope is provided, the fact remains that the periphery of the dense snow core is exposed to the surrounding air through the spaces formed between the separated discharges of the vapor, This permits the snow to entrain air through these spaces and this entrained air, naturally, is carried to the fire and results in supplying combustion supporting oxygen.

It is another primary object of this invention to effect the deflection or some of the carbon dioxide vapor from the several separate discharges into the spaces between such discharges so that these spaces will be sealed or filled up against the admission of air to the dense snow core.

Still another important object of the invention is the provision of a method of and apparatus for producing a fire extinguishing medium discharge that is composed of a dense core of carbon dioxide snow, from which the surrounding air is completely excluded, and a snow core enclosing envelope which is formed of carbon dioxide vapor and water fog, with the water fog being generated in an atmosphere that is formed by the carbon dioxide vapor.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a front elevational view of one form of fire extinguishing discharge apparatus embodying this invention,

Figure 2 is a transverse sectional view taken on line 2--2 of Fig. 1,

Figure 3 is a perspective view of a water fog generating and carbon dioxide vapor deflecting head which is illustrated in Figs. 1 and 2 as being employed in suitable numbers as a part of v the discharge apparatus,

Figure 4 is a transverse sectional view of the head shown in detail in Fig. 3,

Figure 5 is a front elevational view of .a modified form of fire extinguishing discharge appara-- tus embodying this invention, and

Figure 6 is a transverse sectional view taken on line liof Fig. 5.

In the drawings, wherein for the purpose of illustration is shown the preferred embodiment of this invention, and first particularly referring to Figs. 1 to 4 inclusive, the reference character ll designates a pipe line that supplies liquid carbon dioxide to the illustrated discharge apparatus. It should be considered that this supply pipe [I is representative of either a play-pipe" which is attached to the outer end of a fire hose, or of a branch supply pipe that forms a part of a "fixed system." .The pipe II is threaded at its end |2 for connection to the shank or stem l3 of the discharge apparatus. This shank or stem is provided with a bore I4 through which liquid carbon dioxide is delivered to the interior of the body of the discharge apparatus. The forward end I5 01 this bore communicates with the interior of a deflector element and cooperates with this element to form a flow path for the liquid carbon dioxide. Formed on the outer end of the shank or stem I3 is a radially extending flange l6 that is formed with a circular series of orifices I! through which the liquid carbon dioxide is released to permit it to suddenly expand so that its pressure will drop below 75 pounds per square inch, absolute, which will cause all or a major portion of the liquid to flash and form a mixture of snow and vapor. A circular series of threaded openings 3, also, is formed in the flange l6 for a purpose to be explained at a later point. The exterior of the shank or stem I3 is provided with a rearwardly curved or flared surface I9 that terminates in a rearwardly facing shoulder 20.

The above referred to deflector element is identified by the reference character 2| in Figs. 1 and 2. The annular flange I6 of the shank or stem I3 is employed for mounting this deflector element and the series of screws 22, threaded into the holes l8 of the flange attaches the deflector element to the shank or stem. By inspecting Fig. 2, it will be noted that the deflector element 2| is partially hollowed out so as to control the direction of flow of the liquid carbon dioxide from the shank bore M to the discharge orifices IT. The interior of the deflector element 2| is provided with a conicaliy shaped projection 23 for this purpose and this projection is axially aligned with the bore l4 of the shank or stem. Radially outwardly of the projection 23 the interior of the deflector element 2| is provided with the curved surface 24 that is utilized to change the direction of flow of the liquid carbon dioxide so that it will be directed rearwardly through the discharge orifices H. The rear portion of the deflector element 2| is belled or curved outwardly at 25 to form an internal, curved surface 26 that lies opposite to and cooperates with the exteriorly curved surface IQ of the shank or stem I3. It is clearly shown by Fig. 2 that these two cooperating, curved surfaces i9 and 26 diverge with respect to each other in any radial section to form an annular passageway that gradually increases in thickness or depth to permit further expansion of the released carbon dioxide so that the pressure of the same will be certain to drop below the aforesaid 75 pound pressure value to provide for complete flashing of all of the liquid carbon dioxide to a mixture of snow and vapor.

The front portion of the deflector element 2| is illustrated in Figs. 1 and 2 as being formed with radially extending ribs 21 to form therebetween the valleys 28. These valleys are provided with curved inner surfaces 29 that function to deflect forwardly or axially of the discharge apparatus any of the medium which comes in contact with the same.

Fig. 2 clearly shows that the deflector element 2| and the cooperating portionof the shank or stem III are enclosed within a chambered body or casing which is formed by the inner portion 30 and the outer portion 3|. The inner body or casing portion 30 is dish shaped and is centrally cut away at 32 to permit the inner portion of the shank or stem l3 to pass through the same for engaging the shoulder 20 with the part of the said portion 30 which surrounds the Opening 32. This shoulder 20, therefore, acts as a seat or an abutment for mounting the inner portion 30 of the body or easing. Any suitable means may be provided for securing the casing or body portion 30 to the shoulder portion 20 of the shank or stem, such as by welding or the use of suitable screws. The outer portion 3| of the body or casing is of cylindrical shape and has its inner edge portion telescopically associated with the outer marginal edge portion of the inner body part 30 to provide a suitable joint 33 that may be rendered permanent by welding. It is clearly shown in Figs. 1 and 2 that the body or casing of the discharge apparatus cooperates with the shank or stem I3 to provide a closed rear wall while leaving the front or face of the apparatus entirely open. An annular chamber is formed by the cooperation of the body or casing with the stem or shank l3 and the deflector 2| and this chamber receives the circular series of flow controlling and directing units 34.

These units 34 extend radially of the shank or stem 3 and the deflector element 2| and are equally spaced therearound. Each one of these units includes a semi-circular cr semi-cylindrical band 35 which is flanged at both of its longitudinal edges 36, as best illustrated in Fig. 2. The inner transverse edge 31 of each one of these bands 35 is suitably anchored either in close proximity to or in contact withthe periphery of the flared portion or surface IQ of the stem or shank 3. Each one of these bands 35 has its outer edge 38 terminating in the plane of the outer face of the body or casing portion 3| and the outer edges of the ribs 21 that form a part of the deflector element 2|.

Each one of the flow controlling anddirectin units 34 has its opposite sides formed by wall members 39 which lie inside the edge flanges 36 of the bands 35 and are suitably secured thereto. Figs. 1 and 2 of the drawings clearly show that the opposite side walls of each adjacent pair of units 34 are formed by a single piece of sheet material with the center or intermediate portion of each one of these pieces being designated by the reference character 40. These portions 40 function to bridge the gaps or spaces that would otherwise be formed between the inner edges or sides of adjacent units 34.

These side wall members 39 of the several units 34 are clearly shown in Fig. 2 as having apertures 4| formed therein. This figure also clearly shows that these apertures are formed in the forward halves of the side wall members 39, or relatively close to the outer edges 38 of the bands 35. Mounted within each one of the flow controlling and deflecting units 34 is a plow-shaped deflecting and separating element 42 which is wedge shape in section and is provided with the securing flanges 43 at its sides by means of which the elements 42 may be welded, or otherwise secured in place within their respective units 34. These deflecting and separating elements 43 are shown in Fig. 2 as being arranged with respect to the through the cooperating side wall openings orapertures 4|. Fig. 2 shows these elements 42 as being arranged so that their outer transverse edges 45 are spaced from the inner surfaces of the outer end portions of their associated bands 35. A space or gap is thus left between the inner surface of the band 35 of each unit 34 and the outer edge 45 of its associated element 43 through which extinguishing material may flow to the outer edge 38 of the band 35.

The carbon dioxide discharge apparatus thus far described operates in the following manner. Liquid carbon dioxide, at any desired temperature, and its corresponding vapor pressure, will be delivered by the pipe line H to the bore l4 of the shank or stem l3 and will flow as a liquid to the discharge orifices I1. In leaving these orifices, the liquid carbon dioxide expands suddenly and drops in pressure to such an extent that it flashes and vapcrizes. The carbon dioxide that enters the space formed between the outwardly flared surfaces [3 and 25, therefore, takes the form of a mixture of snow and vapor. A certain percentage of the liquid carbon dioxide passing through the oriflces II will flash into snow as a result of the self-cooling action that is produced. The percentage of snow yield will depend upon the temperature of the liquid carbon dioxide that is provided to the discharge apparatus. In other words, a mixture of snow and vapor will be discharged from the peripheral mouth that is formed by the outer edges of the curved surfaces l9 and 26.

As it leaves this peripheral mouth, the snow and vapor mixture will be flowing in a truly radial direction and certain portions of the mixture will pass directly into the various flow controlling and directing units 34. The remainder of the mixture will be split and deflected laterally in opposite directions by the axially extending portions 40 of the sidewall forming pieces 39. These deflected portions of the mixture, therefore, will be directed into the several units 34. The flow controlling and directing units 34, through the medium of their curved outer bands 35, will deflect the flowing snow and vapor mixture from its straight line, radial path and will convert this radial flow into a curvilinear flow or motion. As the carbon dioxide snow of the mixture is many times more dense than the vapor, and as the velocity of both of these components is the same, the snow offers more resistance to the deflecting forces exerted by the obstructing, curved bands 35 with the result that the snow will be moved to the outer portion of each one of these curvilinear flow paths. The snow, in seeking this outer portion of each path, will crowd or force the vapor inwardly away from the inner surface of the curved band that forms the path. Therefore, the difference in density between the snow and the vapor effects a segregation of these two components. The snow is segregated at or close to the outer Surface of each one of the curvilinear paths and the vapor is segregated on the inner side of each path.

As the segregated snow and vapor reach the outer side of each one of the flow controlling and directing units 34, the snow passes through the gap or space left between the inner surface of its band 35 and the outer edge of its flow splitting and separating element 42. The inwardly displaced or segregated vapor strikes the sloping surfaces 44 of the various elements 42 and is directed laterally through the side wall apertures 4| into the portions of the body or casing which lie between adjacent units 34. The segregated and separated snow passes radially outwardly beyond the edges 33 of the several bands 33 and is directed into the valleys 23 of the deflector element 2|. The curved inner surfaces 23 of these valleys deflect the snow so that it will flow into the atmosphere in an axial direction with respect to the entire apparatus. This. discharge of all of the separated snow from all of the units 34 causes the same to be assembled into a compact, dense stream. The separated vapors will leave the spaces between the adjacent units 34 and will flow in an axial direction relative to the discharge apparatus. The vapor is in this way discharged outwardly of the dense snow core portion of the stream. Because the areas of discharge for the vapor are spaced distances equal to the width of the flow controlling and directing units 34, the vapor discharges will be separated from each other immediately adjacent the front face of the apparatus. However, the vapor discharges will blend together a short distance in advance of the apparatus and will form a surrounding or enclosing vapor tube for the compact, dense snow core of the composite discharge stream. Because of this spacing of the separate vapor discharges, it will be appreciated that the compact, dense snow core is exposed. to the air of the surrounding atmosphere and unless some means are provided for preventing such an action, air can be sucked radially inwardly of the discharge apparatus at the locations of the several flow controlling and directing units 34 and this inwardly drawn air will be entrained by the dense snow core.

From this description of the mode of operation of the discharge apparatus for the liquid carbon dioxide, it will be appreciated that there is provided a discharge stream which is of substantially cylindrical shape in transverse section. Fig. 2 of the drawings shows dotted lines A and B which are intended to represent the peripheral margins of this stream on the section of this figure. The dotted lines C and D are intended to illustrate the peripheral margins of the compact, dense snow core. It will be appreciated, therefore. that the margins of the vapor tube or envelope are represented by the dotted lines A-C and B-D.

The apparatus for generating and projecting the water fog that is to be combined with the carbon dioxide discharge now will be described. A hollow water supplying manifold. or ring 46 surrounds the outer edge portion of the body or casing part 3! and is suitably secured thereto by means of the several branch pipes 41 which are connected to the inner side of the ring 46 and pass through suitable openings formed in the body or casing part 3|. A water feed pipe 48 is suitably connected to the nipple 49 that is attached to the manifold or ring 43 at any suitable point. This pipe 48 delivers water to the ring or manifold and this water flows through the several branch lines 41 at a uniform rate. The water supply to the ring or manifold 46 may be under any suitable pressure head but it has been determined that the best water fogging action is obtained when pressures ranging from pounds to 200 pounds per square inch are employed.

By inspecting Fig. 1, it will be seen that the various branch lines 41 extend into the carbon dioxide vapor discharge spaces that are located between adjacent pairs of flow controlling and directing units 34. The inner end of each one of these branch lines 41 has suitably mounted thereon a head 50. One of these heads is shown in detail in Figs. 3 and 4. Each head has a hollowed out box-like main body portion 5!, the interior of which communicates with the bore of a branch line 41 so that water is delivered to the interior of each one of these box-like bodies. -The front face of each box-like body is formed by the two angularly arranged wall portions 52 and 53. These wall portions are provided with a suitable number of discharge apertures 54 and 55 respectively. Due to the angular arrangement of the wall portions 52 and 53, and the opposed positions of the apertures 56 and 55, the water streams discharged through opposed apertures will impinge with the result that the Water will be thoroughly atomized to produce the desired Water fog. By inspecting Fig. 1, it will be seen that the fog generated by each head 55 will be protected or shielded from the surrounding atmosphere by the carbon dioxide vapor that is discharged at the locations identified by the reference character a. The generated water fog, also, will be shielded from the dense snow core by the carbon dioxide vapor that is discharged through the areas identified by the reference character 1).

Figs. 1, 3 and 4 disclose laterally projecting wings 56 as being formed on the opposite sides of the box-like body portions 5i of the several heads 50. The inner sides of these wings 56 are of wedge shape, as indicated by the reference character 51. It will be appreciated, therefore, that these laterally projecting wings 56 and their Wedge shaped rear surfaces 51 will function to deflect or spread circumferentially of the entire discharge apparatus the carbon dioxide vapor which would normally flow axially through the spaces occupied by these several heads 50. This circumferentially deflected vapor will function to close or seal ofi the spaces or areas lying in front of the flow controlling and directing units 34 with the result that these spaces will no longer be open for the passage of air from the surrounding atmosphere into the compact, dense snow core. The circumferentially deflected carbon dioxide vapor that leaves the outer edges of the wings 56 will additionally seal off or close the remaining two sides of the zones in which the water fog is generated by the everal heads. It will be appreciated, therefore, that the water fog is generated by each head 50 in a carbon dioxide vapor atmosphere. Consequently, carbon dioxide vapor will fill the voids left between the individual water droplets or particles of the fog. It further will be noted that the generated fog will be projected in the carbon dioxide vapor portion of the composite discharge; i. e., the annular area defined by the dotted lines A and 3-D of Fig. 2.

Figs. and 6 disclose a modified form of carbon dioxide and water fog discharging apparatus. The carbon dioxide discharging portion of this modification is identical with the carbon dioxide discharging apparatus of Figs. 1 and 2 and for that reason the same reference characters will be applied to identical elements and a second detail description of these elements will not be presented.

The water fog generating mechanism of the embodiment shown in Figs. 5 and 6 is some what different than the fogging mechanism previously described. In this second embodiment,

the water supplying manifold or ring 58 is located at the rear of or in back of the carbon dioxidedischarge apparatus. This manifold or ring receives its supply of water under pressure from the pipe line 59 that is connectedto the ring by the nipple 50.

A suitable number of branch lines ii are connected to the water supply manifold or ring 58 and extend axially of the carbon dioxide discharge apparatus at the inner sides of the several spaces through which the carbon dioxide vapor flows to the discharge face of the apparatus. That is to say, these branch lines 6i lie parallel to and just outside of the connecting portions 40 of the side wall forming pieces 39.

To the front end of each one of these branch lines 6| there is connected a-hollow water fogging head 62. Each one of these heads has its front face formed by the two angularly arranged wall portions 63 and 6t. Discharge apertures 65 and 66 are formed in these wall portions 65 and 64 respectively. The'apertures 65 and 66 of each discharge head are arranged in radial alignment with respect to the entire discharge apparatus and, due to the angular relation of the wall portions 63 and Ed in which the apertures are formed, the streams of water discharged through each pair of apertures will impinge to eifect fog generation.

. It will be obvious from an inspection of the two figures, and particularly Fig. 5, that the water fo generated by the various heads 62 will be projected into both the vapor and the snow portions of the carbon dioxide discharge stream.

Also, the water fog generated by all of the heads 52 will have the voids between the individual water droplets filled with carbon dioxide instead of air.

This discharge apparatus of Figs. 5 and 6 clearly is not as efllcient or effective as the discharge apparatus of Figs. 1 to 4 inclusive. The deflciencies of this modification result from the failure to deflect or spread some of the dischargin vapor circumferentially to fill in or seal the spaces or gaps that are produced by the flow controlling and deflecting units 34. Additionally, it has been determined that a more efficient, effective composite discharge is produced when the water fog is mixed with the carbon dioxide por only.

It is to be understood that the forms of this invention herewith shown and described are to be taken as preferred examples of the same and that various changes in practicing the hereindescribed method, and in the shape, size, and arrangement of parts of the apparatus shown as being capable of carrying out the method, may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim:

1. A method of dischargin a fire extinguishing medium, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid to produce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, generating water fog entirely independently of any force exerted by the projected snow and vapor and at a location that is completely surrounded by the carbon dioxide stream so that the voids between the droplets of the fog will be fllled with carbon dioxide, and so projecting the water fog that it will be carried to the point of application by the carbon dioxide stream.

2. A method of discharging a fire extinguishing medium, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid to produce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, separately generating water fog by the impingement of streams of water within the confines of the carbon dioxide stream so that the voids between the droplets of the fo will be filled with carbon dioxide, and so projecting the water log that it will be carried to the point of application by the carbon dioxide stream.

3. A method of discharging afire extinguishing medium, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid to produce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, separately generating water fog at a plurality of points distributed over the cross section of the carbon dioxide stream so that the voids between the droplets of the fo will be filled with carbon dioxide, and s projecting the water fog that it will be carried to the point of application by the carbon dioxide stream. I

4. A method of discharging a fire extinguishin medium, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid to produce snow and vapor, projecting the snow and vapor into the atmosphere in the form of a stream, separately generatin water fog at a plurality of points distributed over the cross section of the carbon d1? oxide stream by the impingement of two streams of water at each point so that the voids between the droplets of the fog will be filled with carbon dioxide, and so projecting the water fog that it will be carried to the point of application by the carbon dioxide stream.

5. A method of discharging a. fire extinguishing medium, comprising efiecting sudden release of liquid carbon dioxide to lower its pressure sufficiently to form a mixture of snow and vapor, effecting separation of the snow and vapor from each other, formin the separated snow and vapor into a composite discharge stream, separately generating water fog within the confines of the carbon dioxide stream so that the voids between the droplets of the fog will be filled with carbon dioxide, and so projecting the water fo that it will be carried to the point of application by the carbon dioxide stream.

6. A method of discharging a fire extinguishing medium, comprising effecting sudden release of liquid carbon dioxide to lower its pressure sufficiently to form a mixture of snow and vapor, effecting separation of the snow and vapor from each other, forming the separated snow and vapor into a composite discharge stream, separately generating water fog within the confines oi the carbon dioxide vapor portion of the stream so that the voids between the droplets of the fog will be filled with carbon dioxide vapor, and so projecting the water fog that it will be carried to the point of application by the carbon dioxide vapor portion of the stream.

7. A method of discharging a fire extinguish ing medium, comprising efiecting sudden-'release of liquid carbon dioxide to lower its pressure sufficiently to form a mixture or snow and vapor, efiecting separation of the snow and vapor from each other, formin the separated snow and vapor components into a composite discharge stream with the vapor shielding the snow from the surrounding atmosphere, separately generating water fog within the confines of the carbon dioxide vapor portion of the stream so that the voids between the droplets of the fog will be filled with carbon dioxide vapor, and so projecting the water fog that it will be carried to the point of application by the carbon dioxide vapor portion of the stream.

8. A method of discharging a fire extinguishing medium, comprising efiecting sudden release of liquid carbon dioxide to lower its pressure sufficiently to form a mixture of snow and vapor, effecting separation of the snow and vapor from each other, forming the separated snow and vapor component into a composite discharge stream, separately. generating water fog at a plurality of points distributed over the cross section of the carbon dioxide vapor portion of the stream so that the voids between the droplets of the fog will be filled with carbon dioxide vapor, and .so projecting the water iog that it will be carried to the point of application by" the carbon dioxide vapor portion of the stream.

9. A method of discharging a fire extinguishing medium, comprising effecting sudden release of liquid carbon dioxide to lower its pressure sufficiently to form a mixture of snow and vapor. effecting separation of the snow and vapor from each other, forming the separated snow and vapor into a composite discharge stream with the vapor shielding the snow from the surrounding atmosphere, separately generating water fo at a plurality of points distributed over the cross section of the carbon dioxide vapor portion of the stream so that the voids between the droplets of I the fog will be filled with carbon dioxide vapor, and so projecting the water fog that it will be carried to the point of application by the carbon dioxide vapor portion of the stream.

10. A method of discharging a fire extinguishing medium, comprising discharging carbon dioxide snow and vapor to the atmosphere in the form of a stream in which .the snow :and vapor occupy different portions of the stream cross section, generatin water fog within the confines of the carbon dioxide discharge so that the voids between the droplets of the fog will be filled with carbon dioxide, and forming the carbon dioxide and the water fog into a composite discharge stream.

11. A method of discharging a fire extinguishing medium, comprising discharging carbon dioxide snow and vapor to the atmosphere in the form of a stream in which the snow and vapor occupy different portions of the stream cross section, generatin water fog in the confines of the carbon dioxide vapor portion of the stream so that the voids between the droplets of the fog will be filled with the vapor, and forming the carbon dioxide and the water fog into a comosite discharge stream.

12. A method of discharging a fire extinguishing medium, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of' the liquid to produce snow and vapor, efiecting separation of the snow and vapor from each other, discharging the carbon dioxide to the atmosphere with the separated snow forming a single dense stream and with the separated vapor forming several streams spaced circumferentially around the snow stream, and deflecting some of the vapor circumferentially to fill in the spaces between the several vapor streams to prevent the snow stream from entraining air through said spaces.

13. A method of discharging a fire extinguishing medium, comprising conducting liquid carbon dioxide to a region of release; permitting sudden expansion of the liquid to produce snow and vapor, eiTecting separation of the snow and vapor from each other, discharging the carbon dioxide to the atmosphere with the separated snow forming a single dense stream and with the separated vapor forming several streams spaced circumferentially around the snow stream, generating water fog in the path of each one of the vapor streams so that the voids between the droplets of the fog will be filled with the vapor,

' and so projecting the water fog that it will be carried to the point of application by the carbon dioxide.

14. A method of discharging a fire extinguishing medium, comprising conducting liquid carbon dioxide to a region of release, permitting sudden expansion of the liquid to produce snow and vapor, effecting separation of the snow and vapor from each other, discharging the carbon dioxide to the atmosphere with the separated snow forming a single dense stream and with the separated vapor forming several streams spaced circumferentially around We snow stream, deflecting some of the vapor circumferentially to fill in the spaces between the several streams to prevent the snow stream from entrainin air through said spaces, generating water fog axially outwardly of each point of deflection of the vapor so that the z e of generation will be enclosed in the vapor and the voids between the droplets of the fog will be filled with the vapor, and so projecting the water fog that it will be carried to the point of application by the carbon dioxide.

15. Fire extinguishing apparatus, comprising a hollow body, means for releasing carbon dioxide into said body to permit it to suddenly expand to form carbon dioxide snow and vapor, means in the hollow body to effect discharge of the snow and vapor to the atmosphere as a stream,- and means for generating water fog entirely independently of any force exerted by the projected snow and vapor and at a location that is completely surrounded by the snow and vapor of the carbon dioxide stream so that the voids betweenthe water droplets of the fog will be filled with carbon dioxide and for projecting the generated water fog 50 that it will be carried to the point of application by the carbon dioxide stream.

16. Fire extinguishing apparatus, comprising a hollow body through which a mixture of carbon dioxide snow and vapor passes, means within the body for separating snow and vapor from each other while passing therethrough and for discharging the same to the atmosphere with the vapor shielding the snow from the surrounding atmosphere, and means for generating water fog within the vapor portion of the carbon dioxide discharge so that the voids between the droplets of the fog will be filled with carbon dioxide vapor and for projecting the generated water fog into the flow path of the carbon dioxide stream for entrainment thereby.

17. Fire extinguishing apparatus, com-prising a hollow body, means for releasing liquid carbon dioxide into said body to permit it to suddenly expand to form snow and vapor, means in the hollow body to effect discharge of the snow and vapor to the atmosphere as a stream, and means for generating water fog at a plurality of points distributed over the cross section of the carbon dioxide stream so that the voids between the. droplets of the fog will be filled with carbon dioxide.

18. Fire extinguishing apparatus, comprising a hollow body through which a mixture of carbon dioxide snow and vapor passes, means within the.

body for separating the snow and the vapor from each other while passing therethrough and for discharging the same to the atmosphere with the vapor shielding the snow from the surrounding air, and means for generating water fog at aplurality of points distributed over the path of the vapor discharge so that the voids between the droplets of the fog will be filled with carbon dioxide vapor.

19. Fire extinguishing apparatus, comprising a hollow body through which a mixture of carbon dioxide snow and vapor passes, means witl 'n the body for separating the snow and the vapor from each other while passing therethrough and for discharging the snow as a single dense stream and the vapor as several streams spaced circumferentially around the snow stream, and means located in the path of each vapor stream for deflecting some of the vapor circumferentially to fill in the spaces between the several vapor streams to prevent the snow stream from entraining air through said spaces.

20. Fire extinguishing apparatus, comprising means for discharging carbon dioxide to the atmosphere, and means for generating water fog entirely independently of any force exerted by and at a location that is completely surrounded by the carbon dioxide discharge so that the voids between the droplets of the fog will be filled with carbon dioxide.

21. Fire extinguishing apparatus, comprising means for discharging carbon dioxide snow to the atmosphere as a dense stream, means for discharging carbon dioxide vapor to the atmosphere as several streams spaced circumferentially around the snow stream, and means operatively associated with the carbon dioxide vapor streams for deflecting some of the vapor circumferentially I of the snow stream to fill in the spaces between the vapor streams to prevent the snow from entraining air through said spaces.

HILDING V. WILLIAMSON.

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